The present invention relates generally to improvements in hot metal ladle tilters, and specifically to the provision of a ladle tilter which can readily removably receive a ladle of hot metal thereon from an overhead crane, and thereafter tilt the ladle under positive control to a predetermined angle for skimming of slag from the surface of the metal thereof while the overhead crane is used for other purposes.
In one steel making process, molten blast furnace iron is charged into a ladle supported on an overhead crane. Also charged into the ladle is a quantity of molten slag that serves as an insulation during the transporting of the molten iron from the blast furnace to the next steel making step, typically a basic oxygen furnace. Prior to charging the molten iron into the basic oxygen furnace, the molten slag must be removed from the surface of the molten iron so as not to interfere with the conversion process.
The normal procedure heretofore has been to hold the ladle with the molten iron and slag therein with an overhead crane at the proper angle adjacent to a hydraulic skimming device. The hydraulic skimming device has an arm carrying on the outer end thereof a blade shaped like the common garden hoe which is used to scrape the slag from the surface of the molten metal onto the underlying floor or into a slag pot disposed therebelow. The disadvantages of this procedure are that the overhead crane is tied up and prevented from being used in more economically useful activity, and the control of the tilting of the ladle is not very good whereby the ladle may not be positioned in the proper angle for effective removal of the molten slag therefrom.
Typical prior systems utilizing overhead cranes to hold ladles of molten metal and effect tilting thereof are illustrated in the following U.S. Pat. Nos.: 2,224,906, granted Dec. 17, 1940 to W. S. Fraula; 2,881,488 granted Apr. 14, 1959 to F. M. Schweinberg; 2,987,786 granted June 13, 1961 to F. T. Smith et al.; 3,111,228 granted Nov. 19, 1963 to R. P. Anderson, 3,314,550 granted Apr. 18, 1967 to R. B. McCready et al.; and 3,874,514 granted Apr. 1, 1975 to R. Wilson. All of these prior art patented systems tie up the overhead crane while the ladle of molten metal is tilted and the slag removed from the surface of the molten metal.
Certain prior systems dealing with ladles of molten metal do not utilize overhead cranes whatsoever, but permanently mount the ladle on a tilting mechanism. Examples of such prior art systems are illustrated in the following U.S. Pat. Nos.: 3,693,960 granted Sept. 26, 1972 to K. H. Golde et al.; and 3,784,178 granted Jan. 8, 1974 to M. Wernli. Neither of these prior art patents show the concept of utilizing an overhead frame to deposit a readily movable ladle temporarily upon a ladle tilter for removal of slag from the surface of the molten metal therein.